The presently disclosed subject matter relates to a biological information measuring apparatus and a blood pressure analyzing method, and program which invasively measure the blood pressure of the subject.
In patient monitoring, the blood pressure is regarded as an important index. For a severe patient, particularly, it is usual to invasively monitor the arterial and venous pressures. In the invasive blood pressure measurement, a catheter or the like is placed in a vessel or the heart, and a blood pressure waveform or a blood pressure value is continuously measured.
The heart exists in the chest cavity, and hence an invasive blood pressure waveform is affected by variation of the intrapleural pressure due to the respiration of the patient, thereby causing a problem in that the blood pressure waveform and the blood pressure value are not correctly obtained. For example, the central venous pressure (CVP) in the vicinity of the right atrial is low, and hence markedly affected by the respiratory variation. Moreover, parameters of the low-pressure system may be affected not only by the respiratory variation, but also by body motion or the like.
According to a related art, to suppress such influences of respiratory variation and the like on an invasive blood pressure waveform, an averaging process is performed on obtained values of the blood pressure.
According to another related art disclosed in JP2010-200901A, a biological signal measuring apparatus is configured to calculate blood pressure in synchronization with a respiratory waveform obtained by a respiratory sensor.
However, the averaging process has a problem in that, in a case in which a large influence is exerted by respiratory variation or the like, sufficient effect cannot be obtained. The related art disclosed in JP2010-200901A requires a respiratory waveform sensor in addition to equipments for measuring the blood pressure.